This description of embodiments of an invention generally relates to electroplating systems and more particularly, to an improved shielding apparatus and method to improve the electric field current distribution in electroplating systems.
In accordance with one embodiment of the present invention, an electroplating system capable of controlling the thickness of a metal film electrodeposited onto a substrate is provided. The electroplating system includes a standard electroplating apparatus and a non-conductive shield having a certain size and one or more aperture openings that is disposed in the electroplating apparatus to selectively alter or modulate the electric field between the anode and the plating surface in this embodiment and thereby control the electrodeposition rate across the area of the plating surface.
The shield is disposed between the anode and the cathode. As a result, the electric field is modulated so that a desired time-averaged electric field current-density is applied to every point on the plating surface. Because the electrodeposition rate depends in part on the characteristics of the electric field, the uniformity of the thickness profile of the electrodeposited metal can be manipulated by the size of the shield and of the shield aperture(s).